During construction of steel frames and trusses, individual members such as beams and columns are connected together to form a structure. Conventionally, two-dimensional gusset plates are used to connect steel members with either welding or bolts, or their combinations.
However, connecting steel beams requires a degree of physical fitness and expertise that can make it a difficult job. Typically, each connection is custom fit on site while steel members are held in place. The labor cost of welders assembling connectors on site can be prohibitive. Moreover, the time to construct a structure is lengthened by the connections because adjacent members cannot be added until a supporting member is secured.
Furthermore, welding congestion, which constrains deformation capability of a connection, has been a major structural problem for conventional steel structural connections for years. Under cyclic seismic load conditions, the welding congestion creates a stress concentration in three-dimensional tensile stress status, and causes unwanted brittle tensile failure.
What is needed is a technique to allow stronger, more ductile connections that can be installed faster at lower cost.